This invention relates to a motorcycle and more particularly to an improved induction system for a motorcycle that permits a compact arrangement with a highly effective intake system.
As is well known, motorcycles offer considerable design problems because of their relatively small size and compact nature. That is, the components of the motorcycle must be designed so as to achieve their intended purpose in a facile manner while at the same time avoiding intrusion with the other components of the motorcycle and their function.
As a specific example, it has been proposed to employ a suspension for the rear wheel of the motorcycle in which a single suspension element (normally a combined spring, tubular shock absorber) is employed. In order to employ such a single suspension element for the rear suspension, it is desirable if not necessary to place this suspension element on or near a plane passing through the longitudinal center of the motorcycle. As a result, the suspension element must be positioned at least in part beneath the motorcycle seat. However, the engine is also located in this area and frequently the engine induction system including the carburetor extends to the rear of the engine and in proximity to the suspension element. As a result, the induction system must clear the suspension element and these two components should not interfere with the operation of the other.
One way of avoiding such interference would be to position the engine at a lower than desired level in the motorcycle. Such lowering of the engine, however, has the effect of reducing the ground clearance of the motorcycle. Alternatively, interference between the induction system and specifically the carburetor and the suspension element may be avoided by shortening the overall height of the engine. This also gives rise to problems, particularly if it is desirable to use an engine of large displacement. Such large displacement engines, particularly if of the single cylinder four-cycle type, occupy considerable space and their induction system may well interfere with a suspension element of the type wherein a single suspension element is employed for the rear wheel of the motorcycle.
In addition to the aforenoted problems, it is the common practice to employ a carburetor for motorcycle engines of the sliding piston throttle valve type. With a large displacement engine, the carburetor itself also has a large displacement and large bore and hence the sliding piston throttle valve requires additional clearance. This, of course, further aggrevates the problem of positioning all of the components in such a location that they can operate efficiently and without interference from the others.
In addition to the problem of providing clearance between the various components and optimum operation, the arrangements as aforedescribed can cause the carburetor of the engine to be positioned in a location wherein servicing is extremely difficult. That is, if the engine is raised to such a level as to provide the desired ground clearance and if the carburetor is positioned so as to clear the suspension element, the carburetor itself may be positioned in a relatively inexcessible location with prior art type of induction systems.
It is, therefore, a principal object of this invention to provide an improved motorcycle configuration wherein maximum power can be achieved and the components will not interfere with each other.
It is another object of the invention to provide an improved induction system for a motorcycle having a rear suspension that embodies a single suspension element without sacrificing ground clearance or engine performance.
It is another object of this invention to provide a compact, high efficiency induction system for a motorcycle.